A lamp holder assembly for use with an incandescent fixture includes a first housing having a central body portion and a protruding portion surrounded by a base shell consisting of an insulative second housing and an electrically conductive shell. A first electrical contact means is coaxially disposed...http://www.google.ca/patents/US4660906?utm_source=gb-gplus-sharePatent US4660906 - Lamp holder assembly having rotatable base shell
